Had both turbos replaced last week due to turbine failure causing a whining noise at high revs. This week I am having the DCT gearbox replaced due to a very loud rattling noise during driving. My contact at the workshop says its probably the result of the JB4 and increased boost pressure. Have been running map 5 all the time, anyone else had these problems or know one that has? Any input is appreciated.

As the car is out of warranty this is killing me and I dont know if the JB4 and increased power is worth it.

Had both turbos replaced last week due to turbine failure causing a whining noise at high revs. This week I am having the DCT gearbox replaced due to a very loud rattling noise during driving. My contact at the workshop says its probably the result of the JB4 and increased boost pressure. Have been running map 5 all the time, anyone else had these problems or know one that has? Any input is appreciated.

As the car is out of warranty this is killing me and I dont know if the JB4 and increased power is worth it.

Uhhohh

Have you been logging? The dct should be good for around 500torque, but it automatically starts slipping at around 400torque, at leas its what I have heard. Are you still under warranty or out?

Well, a replacement DCT at BMW is $14000 , this is just the gearbox itself and the labor probably ends up at $2000. Note this is Sweden and everything here is approx. twice as costly as in the US, really do not know why, maybe taxes and VAT.

There is no used gearbox available but I found one in southern Germany and the seller claims it comes from a BMW Z4 test car from 2009 with only 120miles. Making a long story short I came back from Germany yesterday with the DCT in my trunk and I paid $2950 for almost a brand new DCT gearbox.

Well, a replacement DCT at BMW is $14000 , this is just the gearbox itself and the labor probably ends up at $2000. Note this is Sweden and everything here is approx. twice as costly as in the US, really do not know why, maybe taxes and VAT.

There is no used gearbox available but I found one in southern Germany and the seller claims it comes from a BMW Z4 test car from 2009 with only 120miles. Making a long story short I came back from Germany yesterday with the DCT in my trunk and I paid $2950 for almost a brand new DCT gearbox.

that's a killer deal! I'd glad it worked out for you cheaper. This is actually one thing I'm really worried about for upgrading power, I have a list of things i'd like to do, but there's no telling if it'll shorten the life of the parts considerably or not. I'm not super rich, so the warrantee being voided and higher rate of failure really scare me. I REALLY plan on keeping the car after lease, if it becomes a problem, I wouldn't be as confident about it.

As said the Z4 is out of warranty so this is becoming very expensive. Thats why I appreciate feedback from those with problems from having increased boost pressure. Most people tells me that the JB4 can not cause these problems especially when running the "fail safe" map 5.

Well, a replacement DCT at BMW is $14000 , this is just the gearbox itself and the labor probably ends up at $2000. Note this is Sweden and everything here is approx. twice as costly as in the US, really do not know why, maybe taxes and VAT.

There is no used gearbox available but I found one in southern Germany and the seller claims it comes from a BMW Z4 test car from 2009 with only 120miles. Making a long story short I came back from Germany yesterday with the DCT in my trunk and I paid $2950 for almost a brand new DCT gearbox.

Luckily you ended up saving $11 k on this DCT... Otherwise it would have been horror...

Your 50k+ mile experience is exceptional to some performance car owners who replace clutches at 20-25k miles, and a shock to others who experience 100k miles. I read of many N54 owners anxious to wear out their twins so they can update with larger twins or the latest big single turbo kits. I also know you are in the first wave of e89 owners out of warranty as no one is older than 4 years, if I do the math correct. The opportunity to apply increased boost to a fresh set of turbo and dual clutches is enviable. It's a perspective thing, like lemons and lemonade. Good luck with your return to flight and send pics of the mechanical findings during the rebuild/replace process.

That was one of my reasons for picking up a car with manual transmission. I use ESS stage2 with 1M torque settings on my 35i, so I really had some concerns about the DKG to handle the torque.

I work at the only Ferrari workshop here in Norway, the Ferrari 458 and California uses Getrag gearboxes, same manufactor as the gearbox for Z4 35i.

We have changed half of the double clutch gearboxes on all 458 and Californias that are sold in Norway under warrenty...

The problem is oil leaks and noises from the gearboxes. Ferrari 458 is on their 8th generation of the gearbox from getrag now

So after knowing this, it was an easy choise

A question to my swedish nabour: When you park the Z4 after a spirited drive, do you let the engine run on idle for a few minutes? This really save your turbos lifetime.

I hope you will get your Z in shape soon

Hello Scandinavian neighbour,
I am for the moment in vacation in Croatia with the Z4 and it runs quiet and fine with the new turbos and gearbox. This new DCT shifts very soft and fine but it down shifts somewhat different than the old one. I have also concluded that it occasionally slips in 3rd gear under increased boost and this never happened with the old DCT, at stock boost there is no indication of slippage. I guess this can be related to the DCT coming from a BMW E89 test car and the workshop will try to figure out if this can be fixed with a software update.

What is your figures as to power and torque with the ESS stage 2 and what is the 1M torque settings?

Well,
the car is now quiet and runs very fine and its a true blessing to drive it compared to the very loud rattling noise before. The JB4 is still connected and I have tried map 1 but the DCT slips in 3rd gear under heavy boost so for the moment I am running map 4 which is stock map with all JB4 in dash options active and no indication of slippage.

I will get rid of the car but as I really like the looks of the E89 I will probably go for a low mileage 35is instead with plenty of warranty

Wow, why would you run such aggressive maps for road driving with minimal pushing the car? Atleast if you constantly push the car you get to enjoy it but is it worth atleast 20k of costs for the occasional "pass" or quick burst?

Pick up a used 08 m3 with your money and get 420 hp out of the box without any strain on the car

Well as I understand it map 5 is not that aggressive because of the auto tune function. But there was indeed a lot of power with the rears spinning loose in 3rd gear. So with all facts at hand the very loud rattlin DCT gearbox was probably because of to much power.

Im not sure if JB4 runs higher boost than ESS stg2, but it is certainly "interesting" to hear about at DCT being replaced not because it slips but because of this rattling noise. Due to your experience I switched back to to ESS stg1 yesterday, just in case I still want to keep the car past 100.000kms (more or less 35is power figures and still a ton of fun to drive).

I never use the launch control out of fear for premature slip, but it seems there is more to worry about... I have noticed that mine makes a tiny bit of rattling noise, but only when warm, and it is not audible when cruising at low rpm. In other words, currently not a problem worth mentioning at all. But the thing is that I do not remember if it was there also before I installed my ess tune. It is most audible during accelleration if in sport+ mode. Did your noise increase slowly over time or was it just there suddenly? Does people without any tune have the same noise as mine?

And btw can someone confirm if the turbos are worn out more quickly if running high boost even if one does not actually floor it all the time? I always tought that if you did not push it, the turbos would (theoretically) last as long as if the factory map was being used...

I too only run ESS Stage 1 for this reason and I have only "launched" the car once, and that was before any modifications. Hopefully, this will lead to a long DCT and Turbo life with the Stett FMIC and Eisenmann exhaust. We shall see as this car is our "keeper." I felt OEM power was plenty I just hated the lag that has largely vanished with the ESS tune.

Im not sure if JB4 runs higher boost than ESS stg2, but it is certainly "interesting" to hear about at DCT being replaced not because it slips but because of this rattling noise. Due to your experience I switched back to to ESS stg1 yesterday, just in case I still want to keep the car past 100.000kms (more or less 35is power figures and still a ton of fun to drive).

I never use the launch control out of fear for premature slip, but it seems there is more to worry about... I have noticed that mine makes a tiny bit of rattling noise, but only when warm, and it is not audible when cruising at low rpm. In other words, currently not a problem worth mentioning at all. But the thing is that I do not remember if it was there also before I installed my ess tune. It is most audible during accelleration if in sport+ mode. Did your noise increase slowly over time or was it just there suddenly? Does people without any tune have the same noise as mine?

And btw can someone confirm if the turbos are worn out more quickly if running high boost even if one does not actually floor it all the time? I always tought that if you did not push it, the turbos would (theoretically) last as long as if the factory map was being used...

I first noticed the noise in the drivers compartment as a small vibrating sound coming from within the dashboard somewhere between the radio and nav. This sound were present when cruising from approx. 25mph and above. When driving with the roof down there was this rattling noise coming from under the car very much noticeable when passing buildings and fences. This noice was also present from 25mph and above and becoming more and more loud. At first I thought it was two different noises, something rattling within the dashboard and the well known wastegate ratte from under the car but it soon became obvious that it was the same source of the noise.

The noise I had was always present from appr. 25mph and above, it did not matter if I was driving manual or in sports mode. With the new DCT the car is incredible silent, the only noise I sometimes can hear is the rear exhaust flap.

I have never ever used the launch control so this can not me the reason for my DCT problem.

I first noticed the noise in the drivers compartment as a small vibrating sound coming from within the dashboard somewhere between the radio and nav. This sound were present when cruising from approx. 25mph and above. When driving with the roof down there was this rattling noise coming from under the car very much noticeable when passing buildings and fences. This noice was also present from 25mph and above and becoming more and more loud. At first I thought it was two different noises, something rattling within the dashboard and the well known wastegate ratte from under the car but it soon became obvious that it was the same source of the noise.

The noise I had was always present from appr. 25mph and above, it did not matter if I was driving manual or in sports mode. With the new DCT the car is incredible silent, the only noise I sometimes can hear is the rear exhaust flap.

I have never ever used the launch control so this can not me the reason for my DCT problem.

Thanks for explaining this san4ever! Then I definitely do not have the rattling noise problem you had before changing your DCT. In fact mine is completely silent while the engine is cold and at any speeds. The noise I am experiencing only starts after the engine has been warm (90C+) for some time, and only during accelleration. Its barely noticeable and after reading your explaination I will stop worrying about it being the same problem as yours. Thanks again!

__________________

Little known facts about BMW: 1) The N54 is still in production and used in the current Z4 35i and 35is. 2) In a Z4 you can get sport+ steering combined with normal suspension etc by selecting DSC=off. (Update: DSC=off also offers sports steering in the M135i) 3) All Z4s with 19" wheels are still only offered with the worst performing OEM tires ever sold with a DCT equipped BMW (Potenza RE 050 RFT).